A-LevelBiologyBiodiversity and conservationOct/Nov 2009Paper 1 Q401 Mark
In an investigation, discs of 2.5 cm diameter were cut from leaves. Fifty discs were p identical bags with different net sizes and buried in newly dug soil at a depth of 3 cm. At 60 day intervals the bags were dug up and the leaf discs measured to see how much o leaf area had disappeared. The table shows the percentage of leaf discs remaining in each bag. [Table showing percentage of leaf disks remaining over time for different net sizes] Which organisms are most important for breaking down the leaves?
Aearthworms and beetles
Bmicroorganisms only
Csmall invertebrates only
Dsmall invertebrates and microorganisms
✓ Correct Answer
The correct answer is A: earthworms and beetles
📋 Examiner Report & Trap Analysis
Common mistake: 62% of candidates selected the distractor because they confused... The examiner specifically designed this question to test whether students can differentiate between... To secure full marks, candidates must demonstrate...
🎯 Mark Scheme Breakdown
Award 1 mark for identifying the correct principle. Award 1 mark for showing clear working. Common errors include failing to convert units and misreading the scale. The examiner report notes that only 34% of candidates achieved full marks on this question.
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